/*
 * Copyright (c) 2001-2002 Michael David Adams.
 * All rights reserved.
 */

/* __START_OF_JASPER_LICENSE__
 * 
 * JasPer License Version 2.0
 * 
 * Copyright (c) 2001-2006 Michael David Adams
 * Copyright (c) 1999-2000 Image Power, Inc.
 * Copyright (c) 1999-2000 The University of British Columbia
 * 
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person (the
 * "User") obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, and/or sell copies of the Software, and to permit
 * persons to whom the Software is furnished to do so, subject to the
 * following conditions:
 * 
 * 1.  The above copyright notices and this permission notice (which
 * includes the disclaimer below) shall be included in all copies or
 * substantial portions of the Software.
 * 
 * 2.  The name of a copyright holder shall not be used to endorse or
 * promote products derived from the Software without specific prior
 * written permission.
 * 
 * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS
 * LICENSE.  NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER
 * THIS DISCLAIMER.  THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
 * "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.  IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
 * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  NO ASSURANCES ARE
 * PROVIDED BY THE COPYRIGHT HOLDERS THAT THE SOFTWARE DOES NOT INFRINGE
 * THE PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER ENTITY.
 * EACH COPYRIGHT HOLDER DISCLAIMS ANY LIABILITY TO THE USER FOR CLAIMS
 * BROUGHT BY ANY OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL
 * PROPERTY RIGHTS OR OTHERWISE.  AS A CONDITION TO EXERCISING THE RIGHTS
 * GRANTED HEREUNDER, EACH USER HEREBY ASSUMES SOLE RESPONSIBILITY TO SECURE
 * ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY.  THE SOFTWARE
 * IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL
 * SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES,
 * AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL
 * SYSTEMS, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH
 * THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH,
 * PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH
 * RISK ACTIVITIES").  THE COPYRIGHT HOLDERS SPECIFICALLY DISCLAIM ANY
 * EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES.
 * 
 * __END_OF_JASPER_LICENSE__
 */

/******************************************************************************\
* Includes.
\******************************************************************************/

#include <assert.h>

#include "jasper/jas_tvp.h"
#include "jasper/jas_stream.h"
#include "jasper/jas_image.h"
#include "jasper/jas_string.h"
#include "jasper/jas_malloc.h"
#include "jasper/jas_debug.h"

#include "mif_cod.h"

/******************************************************************************\
* Local types.
\******************************************************************************/

typedef enum {
    MIF_END = 0,
    MIF_CMPT
} mif_tagid2_t;

typedef enum {
    MIF_TLX = 0,
    MIF_TLY,
    MIF_WIDTH,
    MIF_HEIGHT,
    MIF_HSAMP,
    MIF_VSAMP,
    MIF_PREC,
    MIF_SGND,
    MIF_DATA
} mif_tagid_t;

/******************************************************************************\
* Local functions.
\******************************************************************************/

static mif_hdr_t *mif_hdr_create(int maxcmpts);
static void mif_hdr_destroy(mif_hdr_t *hdr);
static int mif_hdr_growcmpts(mif_hdr_t *hdr, int maxcmpts);
static mif_hdr_t *mif_hdr_get(jas_stream_t *in);
static int mif_process_cmpt(mif_hdr_t *hdr, char *buf);
static int mif_hdr_put(mif_hdr_t *hdr, jas_stream_t *out);
static int mif_hdr_addcmpt(mif_hdr_t *hdr, int cmptno, mif_cmpt_t *cmpt);
static mif_cmpt_t *mif_cmpt_create(void);
static void mif_cmpt_destroy(mif_cmpt_t *cmpt);
static char *mif_getline(jas_stream_t *jas_stream, char *buf, int bufsize);
static int mif_getc(jas_stream_t *in);
static mif_hdr_t *mif_makehdrfromimage(jas_image_t *image);

/******************************************************************************\
* Local data.
\******************************************************************************/

jas_taginfo_t mif_tags2[] = {
    {MIF_CMPT, "component"},
    {MIF_END, "end"},
    {-1, 0}
};

jas_taginfo_t mif_tags[] = {
    {MIF_TLX, "tlx"},
    {MIF_TLY, "tly"},
    {MIF_WIDTH, "width"},
    {MIF_HEIGHT, "height"},
    {MIF_HSAMP, "sampperx"},
    {MIF_VSAMP, "samppery"},
    {MIF_PREC, "prec"},
    {MIF_SGND, "sgnd"},
    {MIF_DATA, "data"},
    {-1, 0}
};

/******************************************************************************\
* Code for load operation.
\******************************************************************************/

/* Load an image from a stream in the MIF format. */

jas_image_t *mif_decode(jas_stream_t *in, char *optstr)
{
    mif_hdr_t *hdr;
    jas_image_t *image;
    jas_image_t *tmpimage;
    jas_stream_t *tmpstream;
    int cmptno;
    mif_cmpt_t *cmpt;
    jas_image_cmptparm_t cmptparm;
    jas_seq2d_t *data;
    int_fast32_t x;
    int_fast32_t y;
    int bias;

    /* Avoid warnings about unused parameters. */
    optstr = 0;

    hdr = 0;
    image = 0;
    tmpimage = 0;
    tmpstream = 0;
    data = 0;

    if (!(hdr = mif_hdr_get(in))) {
        goto error;
    }

    if (!(image = jas_image_create0())) {
        goto error;
    }

    for (cmptno = 0; cmptno < hdr->numcmpts; ++cmptno) {
        cmpt = hdr->cmpts[cmptno];
        tmpstream = cmpt->data ? jas_stream_fopen(cmpt->data, "rb") : in;
        if (!tmpstream) {
            goto error;
        }
        if (!(tmpimage = jas_image_decode(tmpstream, -1, 0))) {
            goto error;
        }
        if (tmpstream != in) {
            jas_stream_close(tmpstream);
            tmpstream = 0;
        }
        if (!cmpt->width) {
            cmpt->width = jas_image_cmptwidth(tmpimage, 0);
        }
        if (!cmpt->height) {
            cmpt->height = jas_image_cmptwidth(tmpimage, 0);
        }
        if (!cmpt->prec) {
            cmpt->prec = jas_image_cmptprec(tmpimage, 0);
        }
        if (cmpt->sgnd < 0) {
            cmpt->sgnd = jas_image_cmptsgnd(tmpimage, 0);
        }
        cmptparm.tlx = cmpt->tlx;
        cmptparm.tly = cmpt->tly;
        cmptparm.hstep = cmpt->sampperx;
        cmptparm.vstep = cmpt->samppery;
        cmptparm.width = cmpt->width;
        cmptparm.height = cmpt->height;
        cmptparm.prec = cmpt->prec;
        cmptparm.sgnd = cmpt->sgnd;
        if (jas_image_addcmpt(image, jas_image_numcmpts(image), &cmptparm)) {
            goto error;
        }
        if (!(data = jas_seq2d_create(0, 0, cmpt->width, cmpt->height))) {
            goto error;
        }
        if (jas_image_readcmpt(tmpimage, 0, 0, 0, cmpt->width, cmpt->height,
          data)) {
            goto error;
        }
        if (cmpt->sgnd) {
            bias = 1 << (cmpt->prec - 1);
            for (y = 0; y < cmpt->height; ++y) {
                for (x = 0; x < cmpt->width; ++x) {
                    *jas_seq2d_getref(data, x, y) -= bias;
                }
            }
        }
        if (jas_image_writecmpt(image, jas_image_numcmpts(image) - 1, 0, 0,
          cmpt->width, cmpt->height, data)) {
            goto error;
        }
        jas_seq2d_destroy(data);
        data = 0;
        jas_image_destroy(tmpimage);
        tmpimage = 0;
    }

    mif_hdr_destroy(hdr);
    hdr = 0;
    return image;

error:
    if (image) {
        jas_image_destroy(image);
    }
    if (hdr) {
        mif_hdr_destroy(hdr);
    }
    if (tmpstream && tmpstream != in) {
        jas_stream_close(tmpstream);
    }
    if (tmpimage) {
        jas_image_destroy(tmpimage);
    }
    if (data) {
        jas_seq2d_destroy(data);
    }
    return 0;
}

/******************************************************************************\
* Code for save operation.
\******************************************************************************/

/* Save an image to a stream in the the MIF format. */

int mif_encode(jas_image_t *image, jas_stream_t *out, char *optstr)
{
    mif_hdr_t *hdr;
    jas_image_t *tmpimage;
    int fmt;
    int cmptno;
    mif_cmpt_t *cmpt;
    jas_image_cmptparm_t cmptparm;
    jas_seq2d_t *data;
    int_fast32_t x;
    int_fast32_t y;
    int bias;

    hdr = 0;
    tmpimage = 0;
    data = 0;

    if (optstr && *optstr != '\0') {
        jas_eprintf("warning: ignoring unsupported options\n");
    }

    if ((fmt = jas_image_strtofmt("pnm")) < 0) {
        jas_eprintf("error: PNM support required\n");
        goto error;
    }

    if (!(hdr = mif_makehdrfromimage(image))) {
        goto error;
    }
    if (mif_hdr_put(hdr, out)) {
        goto error;
    }

    /* Output component data. */
    for (cmptno = 0; cmptno < hdr->numcmpts; ++cmptno) {
        cmpt = hdr->cmpts[cmptno];
        if (!cmpt->data) {
            if (!(tmpimage = jas_image_create0())) {
                goto error;
            }    
            cmptparm.tlx = 0;
            cmptparm.tly = 0;
            cmptparm.hstep = cmpt->sampperx;
            cmptparm.vstep = cmpt->samppery;
            cmptparm.width = cmpt->width;
            cmptparm.height = cmpt->height;
            cmptparm.prec = cmpt->prec;
            cmptparm.sgnd = false;
            if (jas_image_addcmpt(tmpimage, jas_image_numcmpts(tmpimage), &cmptparm)) {
                goto error;
            }
            if (!(data = jas_seq2d_create(0, 0, cmpt->width, cmpt->height))) {
                goto error;
            }
            if (jas_image_readcmpt(image, cmptno, 0, 0, cmpt->width, cmpt->height,
              data)) {
                goto error;
            }
            if (cmpt->sgnd) {
                bias = 1 << (cmpt->prec - 1);
                for (y = 0; y < cmpt->height; ++y) {
                    for (x = 0; x < cmpt->width; ++x) {
                        *jas_seq2d_getref(data, x, y) += bias;
                    }
                }
            }
            if (jas_image_writecmpt(tmpimage, 0, 0, 0, cmpt->width, cmpt->height,
              data)) {
                goto error;
            }
            jas_seq2d_destroy(data);
            data = 0;
            if (jas_image_encode(tmpimage, out, fmt, 0)) {
                goto error;
            }
            jas_image_destroy(tmpimage);
            tmpimage = 0;
        }
    }

    mif_hdr_destroy(hdr);

    return 0;

error:
    if (hdr) {
        mif_hdr_destroy(hdr);
    }
    if (tmpimage) {
        jas_image_destroy(tmpimage);
    }
    if (data) {
        jas_seq2d_destroy(data);
    }
    return -1;
}

/******************************************************************************\
* Code for validate operation.
\******************************************************************************/

int mif_validate(jas_stream_t *in)
{
    uchar buf[MIF_MAGICLEN];
    uint_fast32_t magic;
    int i;
    int n;

    assert(JAS_STREAM_MAXPUTBACK >= MIF_MAGICLEN);

    /* Read the validation data (i.e., the data used for detecting
      the format). */
    if ((n = jas_stream_read(in, buf, MIF_MAGICLEN)) < 0) {
        return -1;
    }

    /* Put the validation data back onto the stream, so that the
      stream position will not be changed. */
    for (i = n - 1; i >= 0; --i) {
        if (jas_stream_ungetc(in, buf[i]) == EOF) {
            return -1;
        }
    }

    /* Was enough data read? */
    if (n < MIF_MAGICLEN) {
        return -1;
    }

    /* Compute the signature value. */
    magic = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];

    /* Ensure that the signature is correct for this format. */
    if (magic != MIF_MAGIC) {
        return -1;
    }

    return 0;
}

/******************************************************************************\
* Code for MIF header class.
\******************************************************************************/

static mif_hdr_t *mif_hdr_create(int maxcmpts)
{
    mif_hdr_t *hdr;
    if (!(hdr = jas_malloc(sizeof(mif_hdr_t)))) {
        return 0;
    }
    hdr->numcmpts = 0;
    hdr->maxcmpts = 0;
    hdr->cmpts = 0;
    if (mif_hdr_growcmpts(hdr, maxcmpts)) {
        mif_hdr_destroy(hdr);
        return 0;
    }
    return hdr;
}

static void mif_hdr_destroy(mif_hdr_t *hdr)
{
    int cmptno;
    if (hdr->cmpts) {
        for (cmptno = 0; cmptno < hdr->numcmpts; ++cmptno) {
            mif_cmpt_destroy(hdr->cmpts[cmptno]);
        }
        jas_free(hdr->cmpts);
    }
    jas_free(hdr);
}

static int mif_hdr_growcmpts(mif_hdr_t *hdr, int maxcmpts)
{
    int cmptno;
    mif_cmpt_t **newcmpts;
    assert(maxcmpts >= hdr->numcmpts);
    newcmpts = (!hdr->cmpts) ? jas_malloc(maxcmpts * sizeof(mif_cmpt_t *)) :
      jas_realloc(hdr->cmpts, maxcmpts * sizeof(mif_cmpt_t *));
    if (!newcmpts) {
        return -1;
    }
    hdr->maxcmpts = maxcmpts;
    hdr->cmpts = newcmpts;
    for (cmptno = hdr->numcmpts; cmptno < hdr->maxcmpts; ++cmptno) {
        hdr->cmpts[cmptno] = 0;
    }
    return 0;
}

static mif_hdr_t *mif_hdr_get(jas_stream_t *in)
{
    uchar magicbuf[MIF_MAGICLEN];
    char buf[4096];
    mif_hdr_t *hdr;
    bool done;
    jas_tvparser_t *tvp;
    int id;

    hdr = 0;

    if (jas_stream_read(in, magicbuf, MIF_MAGICLEN) != MIF_MAGICLEN) {
        goto error;
    }
    if (magicbuf[0] != (MIF_MAGIC >> 24) || magicbuf[1] != ((MIF_MAGIC >> 16) &
      0xff) || magicbuf[2] != ((MIF_MAGIC >> 8) & 0xff) || magicbuf[3] !=
      (MIF_MAGIC & 0xff)) {
        jas_eprintf("error: bad signature\n");
        goto error;
    }

    if (!(hdr = mif_hdr_create(0))) {
        goto error;
    }

    done = false;
    do {
        if (!mif_getline(in, buf, sizeof(buf))) {
            goto error;
        }
        if (buf[0] == '\0') {
            continue;
        }
        if (!(tvp = jas_tvparser_create(buf))) {
            goto error;
        }
        if (jas_tvparser_next(tvp)) {
            abort();
        }
        id = jas_taginfo_nonull(jas_taginfos_lookup(mif_tags2, jas_tvparser_gettag(tvp)))->id;
        jas_tvparser_destroy(tvp);
        switch (id) {
        case MIF_CMPT:
            mif_process_cmpt(hdr, buf);
            break;
        case MIF_END:
            done = 1;
            break;
        }
    } while (!done);

    return hdr;

error:
    if (hdr) {
        mif_hdr_destroy(hdr);
    }
    return 0;
}

static int mif_process_cmpt(mif_hdr_t *hdr, char *buf)
{
    jas_tvparser_t *tvp;
    mif_cmpt_t *cmpt;
    int id;

    cmpt = 0;
    tvp = 0;

    if (!(cmpt = mif_cmpt_create())) {
        goto error;
    }
    cmpt->tlx = 0;
    cmpt->tly = 0;
    cmpt->sampperx = 0;
    cmpt->samppery = 0;
    cmpt->width = 0;
    cmpt->height = 0;
    cmpt->prec = 0;
    cmpt->sgnd = -1;
    cmpt->data = 0;

    if (!(tvp = jas_tvparser_create(buf))) {
        goto error;
    }
    while (!(id = jas_tvparser_next(tvp))) {
        switch (jas_taginfo_nonull(jas_taginfos_lookup(mif_tags,
          jas_tvparser_gettag(tvp)))->id) {
        case MIF_TLX:
            cmpt->tlx = atoi(jas_tvparser_getval(tvp));
            break;
        case MIF_TLY:
            cmpt->tly = atoi(jas_tvparser_getval(tvp));
            break;
        case MIF_WIDTH:
            cmpt->width = atoi(jas_tvparser_getval(tvp));
            break;
        case MIF_HEIGHT:
            cmpt->height = atoi(jas_tvparser_getval(tvp));
            break;
        case MIF_HSAMP:
            cmpt->sampperx = atoi(jas_tvparser_getval(tvp));
            break;
        case MIF_VSAMP:
            cmpt->samppery = atoi(jas_tvparser_getval(tvp));
            break;
        case MIF_PREC:
            cmpt->prec = atoi(jas_tvparser_getval(tvp));
            break;
        case MIF_SGND:
            cmpt->sgnd = atoi(jas_tvparser_getval(tvp));
            break;
        case MIF_DATA:
            if (!(cmpt->data = jas_strdup(jas_tvparser_getval(tvp)))) {
                return -1;
            }
            break;
        }
    }
    jas_tvparser_destroy(tvp);
    if (!cmpt->sampperx || !cmpt->samppery) {
        goto error;
    }
    if (mif_hdr_addcmpt(hdr, hdr->numcmpts, cmpt)) {
        goto error;
    }
    return 0;

error:
    if (cmpt) {
        mif_cmpt_destroy(cmpt);
    }
    if (tvp) {
        jas_tvparser_destroy(tvp);
    }
    return -1;
}

static int mif_hdr_put(mif_hdr_t *hdr, jas_stream_t *out)
{
    int cmptno;
    mif_cmpt_t *cmpt;

    /* Output signature. */
    jas_stream_putc(out, (MIF_MAGIC >> 24) & 0xff);
    jas_stream_putc(out, (MIF_MAGIC >> 16) & 0xff);
    jas_stream_putc(out, (MIF_MAGIC >> 8) & 0xff);
    jas_stream_putc(out, MIF_MAGIC & 0xff);

    /* Output component information. */
    for (cmptno = 0; cmptno < hdr->numcmpts; ++cmptno) {
        cmpt = hdr->cmpts[cmptno];
        jas_stream_printf(out, "component tlx=%ld tly=%ld "
          "sampperx=%ld samppery=%ld width=%ld height=%ld prec=%d sgnd=%d",
          cmpt->tlx, cmpt->tly, cmpt->sampperx, cmpt->samppery, cmpt->width,
          cmpt->height, cmpt->prec, cmpt->sgnd);
        if (cmpt->data) {
            jas_stream_printf(out, " data=%s", cmpt->data);
        }
        jas_stream_printf(out, "\n");
    }

    /* Output end of header indicator. */
    jas_stream_printf(out, "end\n");

    return 0;
}

static int mif_hdr_addcmpt(mif_hdr_t *hdr, int cmptno, mif_cmpt_t *cmpt)
{
    assert(cmptno >= hdr->numcmpts);
    if (hdr->numcmpts >= hdr->maxcmpts) {
        if (mif_hdr_growcmpts(hdr, hdr->numcmpts + 128)) {
            return -1;
        }
    }
    hdr->cmpts[hdr->numcmpts] = cmpt;
    ++hdr->numcmpts;
    return 0;
}

/******************************************************************************\
* Code for MIF component class.
\******************************************************************************/

static mif_cmpt_t *mif_cmpt_create()
{
    mif_cmpt_t *cmpt;
    if (!(cmpt = jas_malloc(sizeof(mif_cmpt_t)))) {
        return 0;
    }
    memset(cmpt, 0, sizeof(mif_cmpt_t));
    return cmpt;
}

static void mif_cmpt_destroy(mif_cmpt_t *cmpt)
{
    if (cmpt->data) {
        jas_free(cmpt->data);
    }
    jas_free(cmpt);
}

/******************************************************************************\
* MIF parsing code.
\******************************************************************************/

static char *mif_getline(jas_stream_t *stream, char *buf, int bufsize)
{
    int c;
    char *bufptr;
    assert(bufsize > 0);

    bufptr = buf;
    while (bufsize > 1) {
        if ((c = mif_getc(stream)) == EOF) {
            break;
        }
        *bufptr++ = c;
        --bufsize;
        if (c == '\n') {
            break;
        }
    }
    *bufptr = '\0';
    if (!(bufptr = strchr(buf, '\n'))) {
        return 0;
    }
    *bufptr = '\0';
    return buf;
}

static int mif_getc(jas_stream_t *in)
{
    int c;
    bool done;

    done = false;
    do {
        switch (c = jas_stream_getc(in)) {
        case EOF:
            done = 1;
            break;
        case '#':
            for (;;) {
                if ((c = jas_stream_getc(in)) == EOF) {
                    done = 1;
                    break;
                }    
                if (c == '\n') {
                    break;
                }
            }
            break;
        case '\\':
            if (jas_stream_peekc(in) == '\n') {
                jas_stream_getc(in);
            }
            break;
        default:
            done = 1;
            break;
        }
    } while (!done);

    return c;
}

/******************************************************************************\
* Miscellaneous functions.
\******************************************************************************/

static mif_hdr_t *mif_makehdrfromimage(jas_image_t *image)
{
    mif_hdr_t *hdr;
    int cmptno;
    mif_cmpt_t *cmpt;

    if (!(hdr = mif_hdr_create(jas_image_numcmpts(image)))) {
        return 0;
    }
    hdr->magic = MIF_MAGIC;
    hdr->numcmpts = jas_image_numcmpts(image);
    for (cmptno = 0; cmptno < hdr->numcmpts; ++cmptno) {
        hdr->cmpts[cmptno] = jas_malloc(sizeof(mif_cmpt_t));
        cmpt = hdr->cmpts[cmptno];
        cmpt->tlx = jas_image_cmpttlx(image, cmptno);
        cmpt->tly = jas_image_cmpttly(image, cmptno);
        cmpt->width = jas_image_cmptwidth(image, cmptno);
        cmpt->height = jas_image_cmptheight(image, cmptno);
        cmpt->sampperx = jas_image_cmpthstep(image, cmptno);
        cmpt->samppery = jas_image_cmptvstep(image, cmptno);
        cmpt->prec = jas_image_cmptprec(image, cmptno);
        cmpt->sgnd = jas_image_cmptsgnd(image, cmptno);
        cmpt->data = 0;
    }
    return hdr;
}
